To inspect the anti-tumor effects of PTX3 upregulation on tumor development mediated by TNF-α in vivo, we developed xenograft tumor model by subcutaneously inoculating gastric cancer BGC-823 cells that had been transfected with lentivirus vectors including LV5-PTX3 overexpress PTX3 and the negative control (LV5-NC). This evidence concerns the gene TNF and gastric cancer.